diff options
| author | Michael Brown <mcb30@ipxe.org> | 2022-10-28 16:27:10 +0100 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2022-11-07 11:19:48 +0000 |
| commit | 30243ad73957a2e1cc4aedc3f23be66cdf399f00 (patch) | |
| tree | c0b476b76fed7f2a9c5a3b9ec1ea03f01017a693 /src/crypto | |
| parent | d1bc872a2e3b682169da4dd708dfe143d539eaaf (diff) | |
| download | ipxe-30243ad73957a2e1cc4aedc3f23be66cdf399f00.tar.gz | |
[crypto] Add concept of cipher alignment size
The GCM cipher mode of operation (in common with other counter-based
modes of operation) has a notion of blocksize that does not neatly
fall into our current abstraction: it does operate in 16-byte blocks
but allows for an arbitrary overall data length (i.e. the final block
may be incomplete).
Model this by adding a concept of alignment size. Each call to
encrypt() or decrypt() must begin at a multiple of the alignment size
from the start of the data stream. This allows us to model GCM by
using a block size of 1 byte and an alignment size of 16 bytes.
As a side benefit, this same concept allows us to neatly model the
fact that raw AES can encrypt only a single 16-byte block, by
specifying an alignment size of zero on this cipher.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/crypto')
| -rw-r--r-- | src/crypto/aes.c | 1 | ||||
| -rw-r--r-- | src/crypto/arc4.c | 1 | ||||
| -rw-r--r-- | src/crypto/crypto_null.c | 1 |
3 files changed, 3 insertions, 0 deletions
diff --git a/src/crypto/aes.c b/src/crypto/aes.c index aeeaa1d2c..5200e7760 100644 --- a/src/crypto/aes.c +++ b/src/crypto/aes.c @@ -784,6 +784,7 @@ struct cipher_algorithm aes_algorithm = { .name = "aes", .ctxsize = sizeof ( struct aes_context ), .blocksize = AES_BLOCKSIZE, + .alignsize = 0, .authsize = 0, .setkey = aes_setkey, .setiv = cipher_null_setiv, diff --git a/src/crypto/arc4.c b/src/crypto/arc4.c index 4d98abead..3b6adec19 100644 --- a/src/crypto/arc4.c +++ b/src/crypto/arc4.c @@ -119,6 +119,7 @@ struct cipher_algorithm arc4_algorithm = { .name = "ARC4", .ctxsize = ARC4_CTX_SIZE, .blocksize = 1, + .alignsize = 1, .authsize = 0, .setkey = arc4_setkey, .setiv = cipher_null_setiv, diff --git a/src/crypto/crypto_null.c b/src/crypto/crypto_null.c index 26cfbfc4e..0ad463c3e 100644 --- a/src/crypto/crypto_null.c +++ b/src/crypto/crypto_null.c @@ -84,6 +84,7 @@ struct cipher_algorithm cipher_null = { .name = "null", .ctxsize = 0, .blocksize = 1, + .alignsize = 1, .authsize = 0, .setkey = cipher_null_setkey, .setiv = cipher_null_setiv, |